The disclosed embodiments belong to the field of airplanes and more particularly to airplanes having a fuselage on the rear part of which a tail assembly is fixed.
In a known and currently the most implemented architecture for the production of commercial transport airplanes, an airplane mainly includes a more or less elongated fuselage to which a wing is fixed in a median position along the length of the fuselage and on the rear part of which a tail assembly is fixed, with a horizontal stabiliser and a vertical empennage, including various aerodynamic surfaces to provide the aerodynamic stability of the airplane and the maneuverability thereof using control surfaces associated with the empennages.
FIG. 1 shows an exemplary rear part of a fuselage 2 carrying an assembly of empennages according to the prior art.
To prevent too important a base drag, the rear part of the fuselage is tapered and the section thereof progressively decreases in height and width from a current section of the fuselage corresponding to a rear part of the substantially cylindrical fuselage part towards a much smaller fuselage end section.
This rear part of the fuselage is often called a rear cone because of its general shape close to a truncated cone.
On the rear cone are fixed on the one hand an horizontal stabiliser 10 and on the other hand a vertical empennage or fin 11 composed of specialized aerodynamic surfaces which are fixed on the sides and on the top of the fuselage 2.
This type of empennages, which is well known to airplane designers, however, has at least two main drawbacks.
First, providing empennages in a location of the fuselage with reduced dimensions is structurally complex, considering the efforts to be taken up by the rear fuselage and as regards the installation of the systems, more particularly because of the generally mobile horizontal stabiliser.
Second, because of the reduction of the sections in the rear cone and the volumes occupied by the empennage systems, the pressurized cabin cannot be extended rearwards as far as would be desirable and the rear part of the cabin most often has a reduced width, limiting the possibilities of arrangement of this area of the cabin.
Then, the rear part of the fuselage and the empennages thereof are most often prejudicial as regards mass, wetted area and useful volume of the fuselage.
In an other architecture, the canard airplanes use a horizontal stabiliser no longer positioned at the rear of the fuselage, but on the contrary in the front part of the fuselage, in front of the wing.
This architecture is rarely implemented in comparison with the solution of rear stabilisers except for small airplanes or fighter airplanes for which the aerodynamic problems connected to the canard stabilisers are more easily solved than on commercial airplanes having larger dimensions and having a less controllable payload distribution.
Although in this case, front horizontal stabilisers are distant from and independent of the rear vertical end, it is always necessary to reduce the section of the rear part of the fuselage in a rear cone.
Besides, the installation of the horizontal stabiliser on the fuselage must be made in a pressurized area of the fuselage and is prejudicial for an area of the fuselage where the payload is.